:Product: 0413RSGA.txt
:Issued: 2012 Apr 13 2200 UTC
# Prepared jointly by the U.S. Dept. of Commerce, NOAA,
# Space Weather Prediction Center and the U.S. Air Force.
#
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 104 Issued at 2200Z on 13 Apr 2012
IA.  Analysis of Solar Active Regions and Activity from  12/2100Z
to 13/2100Z:  Solar activity was very low. Region 1455 (N07W19)
produced occasional B-class x-ray flares. It showed gradual spot and
penumbral growth during the period as well as a mix of polarities in
its intermediate and trailer portions, which indicated a beta-gamma
magnetic structure. New Region 1457 (N22E41) was numbered.
IB.  Solar Activity Forecast:  Solar activity is expected to be very
low during days 1 - 3 (14 - 16 April) with a chance for isolated
C-class flares from Region 1455.
IIA.  Geophysical Activity Summary 12/2100Z to 13/2100Z:
Geomagnetic field activity ranged from quiet to minor storm levels
with a brief period of major storm at high latitudes. The increased
field activity was associated with a persistent coronal hole
high-speed stream (CH HSS). Solar winds speeds gradually increased
during the first half of the period (maximum speed 693 km/s at
13/0846Z), then gradually decreased during the second half of the
period (minimum speed 544 km/s at 13/1941Z).
IIB.  Geophysical Activity Forecast:  Geomagnetic field activity is
expected to be at quiet to unsettled levels during days 1 - 2 (14 -
15 April) with a chance for active levels due to persistent CH HSS
effects. Activity is expected to decrease to mostly quiet levels on
day 3 (16 April) as the CH HSS subsides.
III.  Event Probabilities 14 Apr-16 Apr
Class M    05/05/05
Class X    01/01/01
Proton     01/01/01
PCAF       green
IV.  Penticton 10.7 cm Flux
Observed           13 Apr 098
Predicted   14 Apr-16 Apr  100/100/100
90 Day Mean        13 Apr 114
V.  Geomagnetic A Indices
Observed Afr/Ap 12 Apr  011/014
Estimated Afr/Ap 13 Apr  014/020
Predicted Afr/Ap 14 Apr-16 Apr  007/012-010/012-004/005
VI.  Geomagnetic Activity Probabilities 14 Apr-16 Apr
A.  Middle Latitudes
Active                30/25/15
Minor storm           20/15/05
Major-severe storm    01/01/01
B.  High Latitudes
Active                35/30/20
Minor storm           25/20/10
Major-severe storm    01/01/01